Very strange behavior, CoreXY with external drivers

dc42

Do any other motors move when you command the Y motor?
Please check that you really do have +5V on the common 5V feed to the + inputs of the stepper drivers.

Capricorn

no other motors affected by moving Y.
the Voltage at the + inputs of the drivers is 4.56 V

Capricorn

meanwhile i tested another driver for z-motor (have more of them as spare) and also testet to set the
config to cartesian kinematiks. No luck, always x/z move together.... I´m frustrated....

Capricorn

@veti

thank you, for your help, i´m just about cabling the printer. i can test it, when everything else is running.

dc42

Are you sure that the power to your external stepper drivers is stable? I am wondering whether when they are driving the motors, the voltage could be dropping.

Capricorn

@dc42

i test that... but i think so, cause i serve 5V to the board with a extern 50W power supply

Capricorn

@dc42

testet, konstant 4.45V. I take the 5V from the breakout board. Should i take it from the main board?
Or direct of the power supply?

dc42

@capricorn, I mean the main power to your external stepper drivers - 12V, 24V, 36V or whatever you are using.

Veti

@capricorn said in Very strange behavior, CoreXY with external drivers:

i test that... but i think so, cause i serve 5V to the board with a extern 50W power supply

how do you wire the two power supplies? i think the negative needs to be connected between the two, but i am not 100% sure.

Capricorn

@dc42

konstant 41V motors driving , i´m using a 600W power supply

Veti

i dont think 41v is supported

https://duet3d.dozuki.com/Wiki/Choosing_the_power_supply

The Duet 2 (Wifi and Ethernet) work with a VIN supply of between 11V and 25V

Capricorn

@veti
i don´t think so....

Capricorn

@veti

this is the power for the external motor drivers, not to the duet2

Veti

@capricorn

please draw a diagram. this is getting confusing.

including all power supplies and the wires between them.

Capricorn

@veti
that´s easy.

12V and 5V go to the duet2
41V go to the external motor drivers

Veti

and how are the power supplies connected to each other?

Capricorn

@veti

this are 3 different power supplies. one end each to 220V the other end to the 5v/12v input duet2 and 41v to the motor drivers. No direct connection (except 220V) between them.

Veti

see this for the wiring of the duex
https://duet3d.dozuki.com/Wiki/Duex2_and_Duex5_Features#Section_Wiring

the entire wiring is about avoiding current flow between gnd connections.

and in your case you have several non connected gnd connections.

Capricorn

@veti

not suitable for me, because i have no duex2 oder duex5 board. i have the duet2 ethernet and the expansion breakout bord. the breakout board is only connected by the 50Pin connector

Veti

it would still cause a grounding loop.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)

there is also a very specific warning for the duet where you have a separate 5v supply via usb.
see
https://duet3d.dozuki.com/Wiki/USB_ground_loops